Comparative analysis of hot rolling, cold drawing and cold rolling production methods

Comparative analysis of hot rolling, cold drawing and cold rolling production methods of seamless steel pipes:

Seamless steel pipe (SMLS) is an important industrial material and is widely used in petroleum, chemical industry, aviation, nuclear energy and other fields. It has excellent properties such as high strength, corrosion resistance, and high temperature resistance, so it has attracted much attention. However, in order to produce high-quality seamless steel pipes, the choice of production method during the production process is crucial. At present, the main production methods used are hot rolling, cold drawing and cold rolling, each of which has different characteristics and scope of application. A comparative analysis of these three methods will be conducted below.

1. Hot rolling

Hot rolling refers to a method in which the steel billet is heated to a higher temperature and then shaped through a continuous rolling mill under pressure. This method has the advantages of high production efficiency and low cost, and is suitable for the production of large-sized and thick-walled seamless steel pipes. During the hot rolling process, the steel will undergo multiple deformation and heating cycles, resulting in a uniform and detailed structure and improved mechanical properties. However, due to the high heating temperature, it is easy to cause surface oxidation and internal grain growth of the steel, which affects the surface quality and internal structure. Therefore, subsequent surface treatment and heat treatment are required.

2. Cold drawing

Cold drawing refers to the method of reprocessing the hot-rolled steel pipe and forming it through a drawing machine at room temperature. Compared with hot rolling, cold drawing has higher precision and smoothness, and is suitable for producing precision seamless steel pipes. During the cold drawing process, due to the small amount of deformation and slow deformation speed, the internal stress of the steel is effectively eliminated, resulting in seamless steel pipes with better mechanical properties. However, due to high cost and low production efficiency, the cold drawing method is mainly used to produce seamless steel pipes that require high surface quality and dimensional accuracy.

3. Cold rolling

Cold rolling refers to making hot-rolled steel plates or strips into thin-walled seamless steel pipes at room temperature through multiple deformation processes such as pressing, stretching and bending. This method has the advantages of high production efficiency and low cost, and is suitable for the production of small-diameter and thin-walled seamless steel pipes. During the cold rolling process, due to the large amount of deformation and fast deformation speed, multiple passes of pressing are required to achieve the required size and shape. Therefore, the internal stress of the steel is large and defects are prone to occur. At the same time, the cold rolling method will also affect the mechanical properties of the steel, requiring subsequent heat treatment.

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